JP3148971B2 - Speaker diaphragm support structure - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a support structure for a speaker diaphragm of an audio speaker particularly intended for faithful reproduction.

[0002]

2. Description of the Related Art In a so-called dynamic speaker based on the principle of Fleming's left hand, a diaphragm of a speaker has a drive coil for vibrating the diaphragm at any part of its structure, regardless of its shape. The driving coil is supported by a structure having no freedom of movement except in the direction of driving, and is inserted into the magnetic gap.

[0003] In the invention proposed by the inventor of the present invention (described in Japanese Patent Application Laid-Open No. 8-84395) as a speaker which reproduces as a sound faithfully an electric signal applied to a drive coil, the inventor has proposed a diaphragm and a diaphragm. As a structure for effectively supporting the integrated drive coil, a support structure using a flat plate spring having an expandable and contractible shape is employed.

[0004]

The vibrating plate supported by the above-described supporting structure vibrates faithfully in response to an electric signal applied to the drive coil, while exciting the natural vibration of the flat plate spring. The natural vibration of the flat plate spring is expressed as sound by the diaphragm, overlaps with the reproduced sound by the electric signal, and results in impairing the faithful reproduction.
It is an object of the present invention to improve such points.

[0005]

That is, according to the present invention, the natural vibration of the flat plate spring excited by the vibration of the diaphragm by the electric signal overlaps with the reproduced sound by the electric signal.
An object of the present invention is to propose a structure for suppressing the natural vibration of a flat plate spring in order to prevent the faithful reproduction from being impaired.

According to the first aspect of the present invention, in the structure for supporting a speaker diaphragm by a flat plate spring having an expandable and contractible structure, a plurality of free vibrating ends other than the fixed end of the flat plate spring on the diaphragm side. By increasing the weight, the frequency of the natural frequency of the flat leaf spring is reduced, and the frequency of the natural frequency of the flat leaf spring is converted to a low frequency that does not hinder faithful reproduction of music.

According to a second aspect of the present invention, in the support structure for a speaker diaphragm using a flat plate spring having an extendable structure, a sound absorbing sheet is attached to the flat plate spring so as to overlap and cover the flat plate spring. The amplitude of the natural vibration of the flat plate spring is suppressed so as not to hinder faithful reproduction of music.

According to the third aspect of the present invention, in the support structure of the loudspeaker diaphragm by the flat plate spring having the expandable and contractible structure, a combined effect of the effects of the first and second aspects is achieved. It is to try to make it.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Prior to describing the present invention in detail with reference to the accompanying drawings, FIG. 5 and FIG. 6 show a case where the present invention is applied to a flat speaker described in Japanese Patent Application Laid-Open No. 8-84395. Description will be made using the same reference numerals. In these figures, reference numeral 1 denotes a drive coil, which is a rectangular bobbin 2 which is a part of a crosspiece 3 mounted in a cross-girder shape for reinforcing the plane diaphragm 6.
It is wound. The magnetic circuit is mounted so that most of the drive coil 1 in the longitudinal direction is located at a position between the magnetic gaps shown in FIG.

In FIG. 6, reference numeral 4 denotes a magnet whose polarity (N, S) is at the position shown in FIG. 6 with respect to the longitudinal portion 1 'of the drive coil 1 in FIG. Two magnetic circuits are mounted on the longitudinal portion 1 "of the drive coil 1 so that they have opposite polarities to the position shown in FIG. 6. Reference numeral 5 in FIG. 6 denotes a yoke for creating a magnetic gap. is there.

In FIG. 5, a winding frame 2 of a drive coil 1 is fixed to the flat diaphragm.
When an electric signal is input from the terminals 1 a and 1 b to the plane, vibration of the drive coil 1 is transmitted to the plane diaphragm 6. In a vibration system including the drive coil 1, the winding frame 2 and the plane diaphragm 6, one ends of four flat plate springs 7 are fixed to four corners of the winding frame 2 in parallel with the plane diaphragm 6 in a plane. The other end is fixed to the speaker body structure frame 8 and is supported radially from all sides.

FIG. 1 shows the basic form of the flat plate spring 7, which is made of a phenolic resin laminate of a cloth base material, having a thickness of 0.5 mm, a width of 16 mm, a length of 38 mm, and a slit width of 1 mm.
mm, a plurality of slits which are not connected to each other as shown in the figure. The flat plate spring 7 has no degree of freedom in the plane direction of the plate spring at the origin of vibration, and is free only in the vibration direction. Once the vibration system deviates from the origin of vibration once, it expands and contracts according to the amplitude value in the direction connecting the fixed end of the leaf spring and the support end of the vibration system within the elasticity of the leaf spring,
This provides enough freedom to vibrate in the vibration direction of the vibration system. That is, even if the flat plate spring 7 shown in FIG. 1 is connected at two or more places via the diaphragm structure, the flat plate spring 7 does not lose its degree of freedom in the required vibration direction of the diaphragm. The structure of the plate 6 can be supported. Reference numeral 9 in the drawing is a through hole for attaching the flat plate spring 7 to the speaker body structural frame 8 via screws or the like as appropriate.

In FIG. 2, which is a main part of the invention according to claim 1 of the present invention, the mass of each of a plurality of free vibrating ends of the flat plate spring 7 other than the fixed end 10 on the vibrating plate side is increased. In the example shown in the drawing, the smaller one of the weights 11, 12 made of brass is 2 mm □ ×
0.17g at 5mm, larger weight 12 is 2mm □
It is 0.33 g at × 10 mm. Epoxy resin is used for the attachment. By increasing the mass of the free vibration end in this way, the frequency of the natural frequency of the flat plate spring 7 is reduced.

Referring to FIG. 3 which is a main part of the invention according to the second aspect of the present invention, the flat plate spring 7 is provided with sound absorbing sheets 13 on both the front and back surfaces thereof. The frequency of the natural frequency of the spring 7 is reduced, and as the sheets 13 having sound absorbing properties, for example, a wool human silk blended felt having a nominal thickness of 1.6 mm is used. The attachment is made with a synthetic rubber adhesive.

FIG. 4 shows the structure of the main part of the invention according to claim 3 of the present invention. In FIG. 4, the large and small weights 11 and 12 and the sheet 1 having sound absorbing properties shown in FIGS.
By attaching both of them, the frequency of the natural vibration of the flat plate spring 7 is reduced and the amplitude thereof is also reduced.

As described above, by adjusting the weights of the weights 11, 12 and selecting the material of the sound absorbing sheet and the mounting position thereof as required, the natural frequency of the flat plate spring 7 can be obtained with a desired frequency characteristic. It shall be arbitrarily adjusted.

[0017]

By adopting the above-described structure of the present invention, it is possible to suppress the natural vibration of the flat plate spring, and to realize a planar speaker intended for faithful reproduction.

[Brief description of the drawings]

FIG. 1 is a perspective view of an original shape of a flat plate spring which forms a main part of a support structure of the present invention.

FIG. 2 is a perspective view showing a main part of the configuration according to claim 1 of the present invention.

FIG. 3 is a perspective view showing a main part of the configuration according to claim 2 of the present invention.

FIG. 4 is a side view showing a main part of the configuration according to the third aspect of the present invention.

FIG. 5 is an overall perspective view of a flat speaker to which the present invention is applied.

FIG. 6 is a diagram showing a part of a magnetic circuit and showing a relative position between the magnetic circuit and a driving coil.

[Explanation of symbols]

 Reference Signs List 6 diaphragm 7 plate leaf spring 13 sheet having sound absorbing property

Continuation of the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) H04R 7/20 H04R 7/04 H04R 9/04 105

Claims (3)

(57) [Claims] In a supporting structure of a loudspeaker diaphragm by a flat plate spring having an expandable and contractible structure, a mass of a plurality of free vibrating ends other than a fixed end of the flat plate spring on the side of the diaphragm is increased. A speaker diaphragm support structure that reduces the frequency of the natural frequency of the leaf spring. 2. In a supporting structure of a speaker diaphragm by a flat plate spring having an expandable and contractible structure, a characteristic of the flat plate spring is provided.
A support structure for a speaker diaphragm, wherein a sheet having a sound absorbing property is attached so as to overlap and cover the flat plate spring so as to suppress the amplitude of vibration . 3. In a supporting structure of a loudspeaker diaphragm by a flat plate spring having an expandable / contractible structure, the mass of a plurality of free vibrating ends other than the fixed end of the flat plate spring on the diaphragm side is increased.
To reduce the frequency of the natural frequency of this flat leaf spring.
In addition, a sheet having a sound absorbing property is overlapped with the flat plate spring.
So as to cover the natural vibration of the flat plate spring.
A speaker frequency support structure that suppresses amplitude .